FTRACE_SYSCALLS would create events for each and every system call, evenif it had failed to map the system call's name with it's number. Thisresulted in a number of events being created that would not behave asexpected.

This could happen, for example, on architectures who's symbol names areunusual and will not match the system call name. It could also happenwith system calls which were mapped to sys_ni_syscall.

This patch changes the default system call number in the metadata to -1.If the system call name from the metadata is not successfully mapped toa system call number during boot, than the event initialisation routinewill now return an error, preventing the event from being created.